This invention relates to a video processing apparatus and more particularly to a technique for effectuating frame rate conversion by using interpolation frames derived from the frames in the video signal.
Recently, an industrial trend has become prevailing that the frame rate conversion technique is used as means for improving the quality of images displayed on a display apparatus by increasing the number of frames in a video signal so as to suppress such unnatural motions in animations as blurs and motion judder or irregularity. In order to obtain a definite improvement on the animation quality, however, interpolation frames with high precision must be generated. A conventional, high-level method of frame interpolation uses the motion compensation processing wherein a motion vector representing a motion from one frame to another is generated by using the current frame and the frame immediately preceding the current frame. According to this method, the interpolation frames are generated by detecting inter-frame motions depending on the data on the motion vectors. To obtain interpolation frames with high precision requires high precision in the motion vectors. For this purpose, there have been proposed a method wherein motion vectors are searched in two successive stages (e.g. Toshiba Review, Vol. 59, No. 12, (2004)) and a method wherein a smoothing processing is performed by eliminating unwanted motion vectors through comparison among ambient motion vectors (e.g. JP-A-2002-27414 (Paragraph 9, FIG. 9)).
However, such conventional motion compensation processes makes it difficult to obtain precise motion vectors in the case where plural motions take place or plural moving bodies cross their loci of motion, in a scene. As a result, an image breakdown in display may be caused.